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Text File  |  1988-06-21  |  687 b   |  25 lines
  1. %================ key_last/3, key_prev/3 ===========================
  2. DOMAINS
  3.   DB_SELECTOR = mydba
  4.  
  5. PREDICATES
  6.    % List all keys in an index in reverse order
  7.    list_keys(db_selector, Bt_selector)
  8.  
  9. CLAUSES
  10.   list_keys(Db_selector, Bt_selector):-
  11.     key_current(Db_selector, Bt_selector, Key, _),
  12.     write(Key, '\n'),
  13.     fail.
  14.   list_keys(Db_selector, Bt_selector) :-
  15.     key_prev(Db_selector, Bt_selector, _), !,
  16.     list_keys(Db_selector, Bt_selector).
  17.   list_keys(_, _).
  18.  
  19. GOAL
  20. /* You may need to add a path to REGISTER.BIN */
  21.     db_open(mydba,"register.bin",in_file),
  22.     bt_open(mydba,"person_name",BT_SELECTOR),
  23.     key_last(mydba,BT_SELECTOR,_),
  24.     list_keys(mydba,BT_SELECTOR).
  25.